while noddles are cooking, in a large bowl combine the cream of celery, sour cream, 1/2 soup can of milk ( use milk to rinse out rest of cream of celery).
Mix well, then add in 1 cup cheddar cheese and 1 cup of the Parmesan/Romano cheese mix.
Mix well.
Toss in separated slices of pepperoni, about 1/2 of a 6-8 oz package
Mix well.
Noodles should be done, drain well then add to bowl and mix noodles well with mixture.

in a ( measurements) pan, coat pan with Olive oil non stick spray
arrange more pepperoni on bottom of pan
Sprinkle about 1/4 of the container of the french onion on bottom of pan.
Gently scoop in noodles and even out in pan.
Use remaining French onions on top and then use remaining cheese.
You should have about 1/4 of a package of pepperoni left over, make a sandwich out of them while you wait

Place in oven at 350 for 30 mins.
Let sit on counter till cooled a bit, hot cheese can burn the heck out of your mouth.
scoop out and enjoy